“On the forecast track, the center of Florence will approach the coasts of North and South Carolina later tonight, then move near or over the coast of southern North Carolina and northeastern South Carolina in the hurricane warning area on Friday,” the update said.

“A slow motion across portions of eastern and central South Carolina is forecast Friday night through Saturday night.”

The storm is likely to bring significant rain to the Carolinas, where some places could see upwards of 20 inches, the update said. This is expected to cause “catastrophic flash flooding and prolonged significant river flooding.”